public async Task InvokeAsync(HttpContext context, IHeadElementHelperStore store)
{
var filter = new FilterStream(context, store);
try
{
await _next(context);
if (filter.IsCaptured())
{
filter.MemoryStream.Seek(0, SeekOrigin.Begin);
var parser = new HtmlParser();
using var doc = parser.ParseDocument(filter.MemoryStream);
SetDocumentTitle(store, doc);
SetMetaElements(store, doc);
SetLinkElements(store, doc);
filter.MemoryStream.SetLength(0);
var encoding = Encoding.UTF8;
using var writer = new StreamWriter(filter.MemoryStream, bufferSize: -1, leaveOpen: true, encoding: encoding)
{
AutoFlush = true
};
doc.ToHtml(writer, new PrettyMarkupFormatter());
filter.MemoryStream.Seek(0, SeekOrigin.Begin);
await filter.MemoryStream.CopyToAsync(filter.OriginalStream);
}
}
finally
{
filter.RevertResponseBodyHooking();
}
}
private void SetLinkElements(IHeadElementHelperStore store, IHtmlDocument doc, string indentText)
{
if (store.LinkElementCommands.Count == 0)
{
return;
}
var linkTags = doc.Head.QuerySelectorAll("link").Cast <IHtmlLinkElement>().ToList();
SaveDefault(doc, indentText, linkTags);
foreach (var cmd in store.LinkElementCommands)
{
var e = cmd.Element;
var link = linkTags.FirstOrDefault(m => SameLink(m, e));
if (cmd.Operation == LinkElementOperations.Set)
{
if (link == null)
{
link = CreateAndAddToHead <IHtmlLinkElement>(doc, indentText);
linkTags.Add(link);
}
link.Relation = e.Rel;
link.Href = e.Href;
foreach (var(name, value) in new[] {
internal HeadElementHelperService(IServiceProvider services)
{
this._JS = services.GetService <IJSRuntime>();
this._NavigationManager = services.GetRequiredService <NavigationManager>();
this._Store = services.GetRequiredService <IHeadElementHelperStore>();
this._NavigationManager.LocationChanged += _NavigationManager_LocationChanged;
}
private void SetMetaElements(IHeadElementHelperStore store, IHtmlDocument doc)
{
if (store.MetaElementCommands.Count == 0)
{
return;
}
var metaTags = doc.Head.QuerySelectorAll("meta[name],meta[property],meta[http-equiv]").Cast <IHtmlMetaElement>().ToList();
var metaElements = metaTags.Select(m => new MetaElement
{
Name = m.Name ?? "",
Property = m.GetAttribute("property") ?? "",
HttpEquiv = m.HttpEquivalent ?? "",
Content = m.Content
});
SaveDefault(doc, metaElements, "text/default-meta-elements");
foreach (var cmd in store.MetaElementCommands)
{
var meta = metaTags.FirstOrDefault(m =>
(cmd.Element.Name != "" && cmd.Element.Name == m.Name) ||
(cmd.Element.Property != "" && cmd.Element.Property == m.GetAttribute("property")) ||
(cmd.Element.HttpEquiv != "" && cmd.Element.HttpEquiv == m.HttpEquivalent));
if (cmd.Operation == MetaElementOperations.Set)
{
if (meta == null)
{
meta = doc.CreateElement("meta") as IHtmlMetaElement;
if (cmd.Element.Name != "")
{
meta.Name = cmd.Element.Name;
}
if (cmd.Element.Property != "")
{
meta.SetAttribute("property", cmd.Element.Property);
}
if (cmd.Element.HttpEquiv != "")
{
meta.HttpEquivalent = cmd.Element.HttpEquiv;
}
doc.Head.AppendChild(meta);
metaTags.Add(meta);
}
meta.Content = cmd.Element.Content;
}
else if (cmd.Operation == MetaElementOperations.Remove)
{
if (meta != null)
{
doc.Head.RemoveChild(meta);
metaTags.Remove(meta);
}
}
}
}
private static void SetDocumentTitle(IHeadElementHelperStore store, IHtmlDocument doc, string indentText)
{
if (store.Title == null)
{
return;
}
store.DefaultTitle = doc.Title ?? "";
doc.Title = store.Title;
SaveDefault(doc, indentText, store.DefaultTitle, "text/default-title");
}
private static void SetDocumentTitle(IHeadElementHelperStore store, AngleSharp.Html.Dom.IHtmlDocument doc)
{
if (store.Title == null)
{
return;
}
store.DefaultTitle = doc.Title ?? "";
doc.Title = store.Title;
SaveDefault(doc, store.DefaultTitle, "text/default-title");
}
private void SetMetaElements(IHeadElementHelperStore store, IHtmlDocument doc, string indentText)
{
if (store.MetaElementCommands.Count == 0)
{
return;
}
var metaTags = doc.Head.QuerySelectorAll("meta[name],meta[property],meta[http-equiv]").Cast <IHtmlMetaElement>().ToList();
SaveDefault(doc, indentText, metaTags);
foreach (var cmd in store.MetaElementCommands)
{
var meta = metaTags.FirstOrDefault(m =>
(cmd.Element.Name != "" && cmd.Element.Name == m.Name) ||
(cmd.Element.Property != "" && cmd.Element.Property == m.GetAttribute("property")) ||
(cmd.Element.HttpEquiv != "" && cmd.Element.HttpEquiv == m.HttpEquivalent));
if (cmd.Operation == MetaElementOperations.Set)
{
if (meta == null)
{
meta = CreateAndAddToHead <IHtmlMetaElement>(doc, indentText);
metaTags.Add(meta);
if (cmd.Element.Name != "")
{
meta.Name = cmd.Element.Name;
}
if (cmd.Element.Property != "")
{
meta.SetAttribute("property", cmd.Element.Property);
}
if (cmd.Element.HttpEquiv != "")
{
meta.HttpEquivalent = cmd.Element.HttpEquiv;
}
}
meta.Content = cmd.Element.Content;
}
else if (cmd.Operation == MetaElementOperations.Remove)
{
if (meta != null)
{
doc.Head.RemoveChild(meta);
metaTags.Remove(meta);
}
}
}
}
public async Task InvokeAsync(HttpContext context, IHeadElementHelperStore store)
{
var filter = new FilterStream(context, store);
try
{
await this._next(context);
if (filter.IsCaptured())
{
filter.MemoryStream.Seek(0, SeekOrigin.Begin);
var parser = new HtmlParser();
using var doc = parser.ParseDocument(filter.MemoryStream);
var indentText = doc.Head.Descendents <IText>()
.Select(t => t.Data.Trim('\r', '\n'))
.Where(t => Regex.IsMatch(t, @"^[\t ]+$"))
.OrderByDescending(t => t.Length)
.FirstOrDefault() ?? "";
SetDocumentTitle(store, doc, indentText);
this.SetMetaElements(store, doc, indentText);
this.SetLinkElements(store, doc, indentText);
doc.Head.AppendChild(doc.CreateTextNode("\n"));
filter.MemoryStream.SetLength(0);
var encoding = Encoding.UTF8;
using var writer = new StreamWriter(filter.MemoryStream, bufferSize: -1, leaveOpen: true, encoding: encoding)
{
AutoFlush = true
};
// WORKAROUND: The HtmlMarkupFormatter class in AngleSharp doesn't append slash for closing tag, so I implemented custom version of it.
doc.ToHtml(writer, new CustomHtmlMarkupFormatter());
filter.MemoryStream.Seek(0, SeekOrigin.Begin);
await filter.MemoryStream.CopyToAsync(filter.OriginalStream);
}
}
finally
{
filter.RevertResponseBodyHooking();
}
}
private void SetLinkElements(IHeadElementHelperStore store, IHtmlDocument doc)
{
private void SetLinkElements(IHeadElementHelperStore store, IHtmlDocument doc, string indentText)
{
